A dispute between the government and the rights of two older workers will go to the Court of Appeal on Thursday.
John Rutherford and Samuel Bentley, who are in their seventies, want unfair dismissal and redundancy payments.
The men won their case at an employment tribunal in August 2002, but this was overturned by the government on appeal a year later.
Workers over 65 do not have the same employment rights as younger workers under existing legislation.
Mr Rutherford, from Essex, and Mr Bentley, from London, have previously argued under European law that they suffered indirect sexual discrimination because more men than women over 65 continue to work in later life.
During the appeal, the Department of Trade and Industry (DTI) argued that it was incorrect to conclude there was sexual discrimination against men when the majority of the workforce was under 65, and therefore not discriminated against by the law.
Although they lost the employment tribunal appeal, they were given the right to appeal.
Case background
Mr Rutherford, who worked for clothes wholesaler Harvest Town Circle in London, was not given any redundancy payments when he was laid off at 67.
Neither was Mr Bentley, who lost his job as a tailor for London-based Bodner Elen Limited when he was 73.
The men challenged the trade and industry secretary because both their former employers had ceased trading.
Age Concern estimates there are more than half a million employed and self-employed workers over 65.
The government is still committed to implementing a European Union directive on equal treatment, which includes a ban on age discrimination, by 2006.
The Department of Trade and Industry said it would not be commenting in advance of the appeal.